you can use any type of credit card ( you applied in US) in Canada if the store accepts this type of the credit card. keep in mind, do not terminate your US credit card after you come to Canada.
you still need some time to get your new Canadian credit card.
Today I bought a money order in CAD from a bank, for my wife's application fee. The rate is 1.52978 and the comminssion fee is 20USD. So 60 CAD cost me 59.22USD. Almost 1:1.